Chin-up (Underhand Grip)
The Chin-up (Underhand Grip) is a compound bodyweight exercise that builds upper body strength by targeting the latissimus dorsi and biceps. By using a supinated grip, this movement places significant emphasis on arm development while effectively training the back.
Since your body weight acts as the resistance, the AI integrates your logged body weight with rep performance to calculate your true relative strength and progressive overload status. By monitoring HRV and sleep data, the app can detect central nervous system fatigue, which heavily influences maximal pull strength, allowing it to auto-adjust volume or suggest regressions like lat pulldowns on low-recovery days. Additionally, tracking RPE on each set helps the system determine exactly when you have mastered your body weight and are ready for weighted variations.
Form Cues
- Grip the bar shoulder-width apart with palms facing toward you
- Start from a full dead hang with arms completely extended
- Drive your elbows down and back to pull your upper chest to the bar
- Squeeze your biceps and lats firmly at the top of the movement
- Lower yourself under control until your arms are fully straight again
- Don't use momentum or kick your legs to generate upward force
- Don't let your shoulders roll forward or shrug toward your ears
- Don't shorten the range of motion by stopping before arms are straight
- Don't stretch your neck forward just to clear the bar with your chin
Common Mistakes
- Incomplete range of motion
- Excessive swinging or kipping
- Rounding the shoulders forward
- Dropping too quickly on the descent
- Hyper-extending the lower back
Muscles Worked
This exercise primarily targets the latissimus dorsi (lats) to build back width and strength. The underhand (supinated) grip places the biceps in a mechanically advantageous position, making them a primary mover alongside the back muscles, while the forearms and core work constantly to maintain grip and stability.
Primary
Secondary
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